EDGE-CUTTING 6Y0481 - Caterpillar

Illustration 1 g06202433
Cross section of main relief valve
(1) Main control valve
(2) Straight travel control valve
(3) Check valve
(4) Check valve
(5) Main relief valve
(6) Pump 1
(7) Pump 2
(8) Pump 2 delivery line
(9) Pump 1 delivery line
(10) Internal passage
(11) Return passageMain relief valve (5) is located in the main control valve. The main relief valve limits the maximum operating pressure of the travel hydraulic circuit and the implement hydraulic circuits when the machine is at a load condition.The oil delivery from pump 1 (6) enters main control valve (1) through delivery line (9). The oil delivery from pump 2 (7) enters main control valve (1) through delivery line (8). Pump oil flows through check valves (3) and (4) to passage (10). Check valves (3) and (4) ensure that only the higher oil pressure from the pumps flows through passage (10) to main relief valve (5).Closed Position
Illustration 2 g06202510
Main relief valve (closed position)
(12) Passage
(13) Seat
(14) Valve
(15) Spring
(16) Spring chamber
(17) Seat
(18) Poppet
(19) Spring
(20) Passage
(21) Orifice
(22) Return passagePoppet (18) is positioned down against seat (17) by the force of spring (19). Valve (14) is positioned down against seat (13) by the force of spring (15).Pressurized oil in passage (12) flows through orifice (21) into spring chamber (16). The force of the system oil acts